This invention relates in general to storage and handling apparatus and in particular to storage apparatus for a stack of flat, elongated sticks which operates between an automatic stick stacking apparatus and a high speed stick inserter and has a stick reject system for automatically eliminating misaligned sticks from the stack.
In the manufacture of frozen confection products such as popsicles and the like it is necessary to insert a flat, elongated stick into the molded confection product. A commonly assigned application, Ser. No. 613226 for "Stick Inserter," filed of even date herewith by the present applicant, the disclosure of which is incorporated herein by reference, describes a suitable high speed apparatus for inserting the sticks. The inserter requires that the sticks be supplied periodically at a high rate and in a predetermined array. Since the sticks are typically supplied in bulk cartons and are ordered only to the extent that the sticks in a carton are generally parallel, it is necessary to employ a stick stacker to form these sticks into an aligned stack or stacks which are then fed to the inserter. A type of automatic stick stacking apparatus suitable for this purpose is described in U.S. Pat. No. 3,246,773 to Hogkins, as well as in the aforementioned co-pending application.
Although the stacker is capable of operating at a sufficiently high speed to feed aligned sticks to the inserter without production delays, these devices have different modes of operation and limitations in their physical geometry which prevent a direct feed from the stacker to the inserter. The inserter operates in cycles that allow only a brief part of each cycle for a set of sticks to be supplied to a notched cross conveyor. The cross conveyor is designed to receive sticks fed in a downwardly direction onto its upper run with the sticks seating in the notches as the conveyor translates horizontally at a high speed. The stacker, in contrast, operates at a steady rate, forming vertically oriented stacks of aligned sticks by repeatedly adding sticks to the bottom of the stack.
The vertically oriented storage disclosed in Hodgkins generates an aligned vertical stack of sticks to be fed to an inserter. However, once stacked and stored, the sticks are removed from the vertical storage manually, in relatively small groups, by gripping a portion of the stack with a widejawed spring clamp. The group is then carried to a suitable storage device associated with the inserter, typically a set of inclined racks or guideways. The repeated manual transfer of a limited quantity of sticks between the stacker storage and the inserter storage adversely affects both the operating speed and production cost for the entire stick insertion operation.
U.S. Pat. No. 3,478,703 to Peppler discloses a "surge supply" device for stick storage which avoids the manual transfer of groups of aligned sticks from the stacker to the inserter. The Peppler device utilizes a pair of parallel rigid tracks connected at their bottom ends by a flexible rounded bottom portion formed between an outer endless belt and an inner flanged wheel. This bottom portion is movable in a generally vertical direction to provide a variable volume storage capacity. Sticks are inserted by a "sorting apparatus" into the upper end of one track and removed to an inserter at the upper end of the other track.
The Peppler device, although it does provide a direct link between a sorting apparatus and an inserter apparatus, nevertheless suffers from various disadvantages. First, it does not provide any means for eliminating misaligned sticks from the stack. Such misaligned or disarranged sticks are likely to jam the advance of sticks through the surge supply. To clear the jam, production must be stopped while the surge supply is unloaded and the jam is cleared. Second, the Peppler surge supply is adapted to a downward stick insertion and upward stick feed, which is the opposite of the requirements of applicant's aforementioned high speed inserter and the Hodgkins type stacker.
Finally, the Peppler wheel and belt arrangement and its location at the bottom of the stack are conducive to stick misalignment and jam. In normal operation the stack pressure between adjacent sticks is usually sufficient to maintain the sticks in a face-to-face alignment. However, during a low pressure condition such as during initial loading, replacement of a bulk supply carton, or the rapid removal of a large number of sticks, cross-stick forces at the curved bottom region of the surge supply can predominate over the stack or inter-stick pressure causing the sticks to move out of the face-to-face alignment. More specifically, the weight of the wheel and a radial component of the belt tension, as well as differences in the frictional forces acting on the opposite side edges of the sticks, can twist the sticks about their longitudinal axes, against the inter-stick pressure, into an orientation that is likely to cause the sticks to jam.
It is therefore a principal object of this invention to provide a stick storage apparatus that automatically maintains a stack of aligned sticks at a substantially constant stack pressure to feed a high-speed stick inserter with relatively few interruptions due to stick jams.
A further object of the invention is to provide a system for automatically eliminating misaligned sticks from the storage apparatus.
Yet another object is to provide a stick storage device that has a rigid guideway with upward insertion and downward feed that maintains a substantially constant inter-stick pressure.